CN112653690B - Analog demodulation circuit for acquiring message by C interface of ground electronic unit - Google Patents

Abstract

The invention provides a simulated demodulation circuit for acquiring a message by a C interface of a ground electronic unit, which comprises: the interface circuit unit is connected with the interface C of the ground electronic unit and is used for receiving the interface C signal; the mutual inductor T1 is connected with the interface circuit unit and used for collecting voltage induction signals; the C1 signal analog demodulation unit is connected with the mutual inductor T1 and is used for filtering a C1 signal from the voltage induction signal and generating a DBPL code signal; the C6 signal energy detection unit is connected with the mutual inductor T1 and is used for filtering the C6 signal from the voltage induction signal and detecting the energy of the C6 signal; and the signal processing unit is respectively connected with the C1 signal analog demodulation unit and the C6 signal energy detection unit and is used for decoding the DBPL coded signal generated by the C1 signal analog demodulation unit and judging whether the energy of the C6 signal meets the requirement or not. The invention can realize the analog demodulation and the logic decoding of the C1 message signal and simultaneously realize the energy detection of the C6 signal.

Description

The ground electronic unit C interface obtains the message analog demodulation circuit

technical field

The invention relates to the technical field of railway communication signals, in particular to an analog demodulation circuit for obtaining messages from a C interface of a ground electronic unit.

Background technique

In the railway signal system, the ground electronic unit (LEU) is the key equipment for transmitting variable messages in the transponder system. It forms a point signal transmission system with the ground transponder and the on-board antenna. Devices can communicate information at decentralized points.

The LEU needs to send the ground data to the automatic train protection system (ATP) through the C1 signal and the C6 signal. The C1 signal is the message sent by the LEU to the active transponder, and the C6 signal is for the LEU to provide energy to the active transponder interface circuit.

The C interface is the interface between the LEU and the active transponder, and is mainly responsible for transmitting the C1 message signal and the C6 energy signal.

In the actual debugging, a professional instrument is needed to detect whether the above two signals are normal, to detect whether the C6 energy signal meets the energy requirements, and to realize the DBPL decoding of the C1 message signal, so as to meet the on-site LEU sending message verification, and C6 Energy signal inspection requirements. However, the cost of such specialized meters is higher.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a ground electronic unit C interface to obtain a message analog demodulation circuit, which realizes the analog demodulation and logical decoding of the C1 message signal, and simultaneously realizes the energy detection of the C6 signal, and reduces the cost.

In order to achieve the above object, the present invention is realized through the following technical solutions:

A ground electronic unit C interface obtains a message demodulation analog circuit, comprising:

The interface circuit unit is connected with the C interface of the ground electronic unit, and is used for receiving the C interface signal;

The mutual inductance coil T1 is connected to the interface circuit unit and is used for collecting voltage induction signals;

The C1 signal analog demodulation unit is connected to the mutual inductance coil T1, and is used to filter out the C1 signal from the voltage induction signal and generate a DBPL encoded signal;

A C6 signal energy detection unit, connected to the mutual inductance coil T1, is used to filter out the C6 signal from the voltage sensing signal and detect the energy of the C6 signal;

A signal processing unit, respectively connected to the C1 signal analog demodulation unit and the C6 signal energy detection unit, for decoding the DBPL encoded signal generated by the C1 signal analog demodulation unit, and judging whether the energy of the C6 signal is fulfil requirements.

Further, in the above-mentioned ground electronic unit C interface to obtain a message analog demodulation circuit, the interface circuit unit includes: a TVS protection tube, an LC bandpass filter module and a matching resistor, wherein the LC bandpass filter module and all The matching resistor is connected in series with the TVS protection tube in parallel, and the matching resistor is connected in parallel with the input end of the mutual inductance coil T1.

Further, in the above-mentioned analog demodulation circuit of the message obtained by the C interface of the ground electronic unit, an FPGA is used as the signal processing unit.

Further, in the above-mentioned ground electronic unit C interface to obtain the message analog demodulation circuit, the C1 signal analog demodulation unit includes a high-pass filter circuit module, a direct-pass traffic capacitor and a comparison circuit module connected in sequence;

The high-pass filter circuit module is connected to the output end of the mutual inductance coil T1, the voltage sensing signal is filtered out by the high-pass filter circuit module to filter out the C1 signal, and after passing through the DC blocking capacitor, it is connected to the comparison circuit module Generate DBPL encoded signal and output.

Further, in the above-mentioned ground electronic unit C interface to obtain a message analog demodulation circuit, the high-pass filter circuit module includes two parallel branches, one of which includes a series-connected resistor R1 and a capacitor C1, and the other branch. Including resistor R2, the impedances of the two branches are different.

Further, in the above-mentioned analog demodulation circuit of the message obtained by the C interface of the ground electronic unit, the comparison circuit module includes a first DC bias circuit, a second DC bias circuit and a comparator, and the first DC bias The setting circuit generates a first bias voltage, the second DC bias circuit generates a second bias voltage, and the first bias voltage is connected to the first bias voltage through the C1 signal of the DC blocking capacitor, and the second bias voltage is connected to the first bias voltage. The two bias voltages are generated by the comparator to generate a DBPL encoded signal and output through a pull-up resistor.

Further, in the above-mentioned ground electronic unit C interface acquisition message analog demodulation circuit, the C6 signal energy detection unit includes a rectifier circuit module, a filter circuit module and a comparator connected in sequence;

The rectifier circuit module is connected to the output end of the mutual inductance coil T1, the voltage induction signal generates a unipolar level signal through the rectifier circuit module, and the unipolar level signal is connected to the filter circuit module The C6 signal is filtered out, and then compared with the preset level signal by the comparator to detect the energy of the C6 signal.

Further, in the above-mentioned analog demodulation circuit of the message obtained by the C interface of the ground electronic unit, the rectifier circuit module includes a full-bridge diode.

Further, in the above-mentioned ground electronic unit C interface to obtain a message analog demodulation circuit, the filter circuit module includes two branches in parallel, wherein one branch includes two LC circuits connected in series, and the other branch includes filtering. Capacitor C3.

Compared with the prior art, the present invention has the following advantages:

1) The present invention innovatively designs a C1 signal analog demodulation unit, which realizes the characteristics of low cost and strong practicability for the analog demodulation and logic decoding of the C1 message signal, and also innovatively designs a C6 signal energy detection unit in the present invention, Realize the energy detection of C6 signal, which has unique advantages compared with other equipment manufacturers;

2) The demodulation circuit provided by the present invention is simpler and more efficient, and can conveniently make test instruments, which can be applied to field engineering debugging and verification of C interface signals. Real-time demodulation can be realized by simulating demodulation and logic decoding of C1 message signals. And judge the accuracy or bit error rate of the message sent by the LEU, and add the C6 signal energy detection circuit, which enriches the C interface test completion.

Description of drawings

In order to illustrate the technical solution of the present invention more clearly, the following will briefly introduce the accompanying drawings used in the description. Obviously, the accompanying drawings in the following description are an embodiment of the present invention, which is useful to those skilled in the art. In other words, on the premise of no creative work, other drawings can also be obtained based on these drawings:

FIG. 1 is a block diagram of an analog demodulation circuit for acquiring a message through a C interface of a ground electronic unit provided by an embodiment of the present invention;

Fig. 2 is the block diagram of C1 signal analog demodulation unit;

Fig. 3 is the schematic diagram of C signal waveform filtering result in C1 signal analog demodulation unit;

Fig. 4 is the schematic diagram of generating DBPL square wave by comparator in C1 signal analog demodulation unit;

FIG. 5 is a block diagram of the C6 signal energy detection unit.

Detailed ways

The following describes the analog demodulation circuit of the ground electronic unit C interface to obtain the message in detail with reference to FIGS. 1 to 5 and the specific embodiments. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the accompanying drawings are in a very simplified form and all use inaccurate scales, and are only used to facilitate and clearly assist the purpose of explaining the embodiments of the present invention. For the purpose, features and advantages of the present invention to be more clearly understood, please refer to the accompanying drawings. It should be noted that the structures, proportions, sizes, etc. shown in the drawings attached in this specification are only used to cooperate with the contents disclosed in the specification, so as to be understood and read by those who are familiar with the technology, and are not used to limit the implementation of the present invention. Therefore, it does not have technical substantive significance. Any modification of structure, change of proportional relationship or adjustment of size should still fall within the scope of the present invention without affecting the effect that the present invention can produce and the purpose that can be achieved. The scope of the disclosed technical content can be covered.

As shown in FIG. 1 , the analog demodulation circuit of the ground electronic unit C interface acquisition message provided by an embodiment of the present invention includes an interface circuit unit 100, a mutual inductance coil T1, a C1 signal analog demodulation unit 200, a C6 signal energy detection unit 300 and Signal processing unit 400 .

Specifically, the interface circuit unit 100 is connected to the ground electronic unit C interface for receiving C interface signals;

The mutual inductance coil T1, connected to the interface circuit unit 100, is used for collecting voltage induction signals;

The C1 signal analog demodulation unit 200, connected to the mutual inductance coil T1, is used to filter out the C1 signal from the voltage sensing signal and generate a DBPL encoded signal;

The C6 signal energy detection unit 300, connected to the mutual inductance coil T1, is used to filter out the C6 signal from the voltage sensing signal and detect the energy of the C6 signal;

The signal processing unit 400 is respectively connected to the C1 signal analog demodulation unit 200 and the C6 signal energy detection unit 300, and is used for decoding the DBPL encoded signal generated by the C1 signal analog demodulation unit 200, and to determine the Whether the energy of the C6 signal meets the requirements.

Preferably, the signal processing unit 400 may use an FPGA to reduce costs.

The external LEU device connects the C interface signal to the interface circuit unit 100 to realize filtering and impedance matching at the interface end. The voltage induction signal is collected through the mutual inductance coil T1, and is respectively given to the C1 signal analog demodulation unit 200 and the The C6 signal energy detection unit 300 is described. Specifically, the interface circuit unit 100 includes: a TVS protection tube D2, an LC bandpass filter module LC and a matching resistor R8, wherein the LC bandpass filter module LC and the matching resistor R8 are connected in series with the TVS protection The tube D2 is connected in parallel, and the matching resistor R8 is connected in parallel with the input end of the mutual inductance coil T1.

Preferably, the C1 signal analog demodulation unit 200 is implemented by a low-cost RC circuit and a comparator. As shown in FIG. 2 , the C1 signal analog demodulation unit 200 includes a high-pass filter circuit module 201 , a DC blocking capacitor C2 and a comparison circuit module 202 connected in sequence. The high-pass filter circuit module 201 is connected to the mutual inductance coil T1 The output end is connected, the voltage sensing signal is filtered by the high-pass filter circuit module 201 to filter out the C1 signal, and after passing through the DC-blocking traffic capacitor C2, it is connected to the comparison circuit module 202 to generate a DBPL encoded signal and output.

Specifically, the high-pass filter circuit module 201 includes two branches in parallel, one of which includes a resistor R1 and a capacitor C1 connected in series, and the other branch includes a resistor R2, and the impedances of the two branches are different. The voltage sensing signal is processed by the high-pass filter circuit module 201 to suppress the C6 signal (8.8Khz sine wave), so that the C1 signal (564Khz/282Khz square wave) is filtered out. The principle is that under different frequencies, the impedance of the two branches Different, so that the high-frequency signal attenuation is small, the low-frequency signal attenuation is large, and the high-pass filtering is realized to filter out the C1 signal.

After the filtered C1 signal passes through the DC blocking capacitor C2, it is finally connected to the comparison circuit module 202. The comparison circuit module 202 includes a first DC bias circuit, a second DC bias circuit and a comparator U1 , the first DC bias circuit generates a first bias voltage Vref1 (divided by R3/R4), and the second DC bias circuit generates a second bias voltage Vref2 (divided by R5/R6). The C1 signal of the DC blocking capacitor C2 is introduced into the first bias voltage Vref1, and the second bias voltage Vref2 generates a DBPL encoded signal through the comparator U1 and outputs it through a pull-up resistor R7. Among them, the voltage values of Vref1 and Vref2 are equal.

After conditioning by the above conditioning RC circuit, the C signal waveform filtering result is shown in Figure 3, wherein VM1 is the input signal of the high-pass filter circuit module 201, VM3 is the output signal of the high-pass filter circuit module 201, and the left side in Figure 3 is the input high-pass filter. The waveform of the circuit module 201 is the waveform output by the high-pass filter circuit module 201 on the right in FIG. 3 . It can be seen from Figure 3 that the C6 signal (8.8Khz sine wave) is obviously suppressed, and the amplitude is attenuated by about 4 times. The C1 signal (564Khz/282Khz square wave) has little attenuation.

After adding DC bias, the DBPL square wave generated by comparator U1 is shown in Figure 4.

As shown in FIG. 5 , the C6 signal energy detection unit 300 includes a rectifier circuit module 301, a filter circuit module 302 and a comparator U2 connected in sequence. The rectifier circuit module 301 is connected to the output end of the mutual inductance coil T1, so the The voltage sensing signal generates a unipolar level signal through the rectifier circuit module 301, and the unipolar level signal is connected to the filter circuit module 302 to filter out the C6 signal, and then the comparator U2 and the preset The level signals are compared to detect the energy of the C6 signal.

Preferably, the rectifier circuit module 301 includes a full-bridge diode D1, and the filter circuit module 302 includes two branches connected in parallel, wherein one branch includes two LC circuits connected in series, and the other branch includes a filter capacitor C3 .

In this embodiment, the voltage induction signal collected by the mutual inductance coil T1 generates a unipolar level U0 through the full-bridge diode D1 of the rectifier circuit module 301, and the voltage signal U0 is connected to the filter circuit module 302, The L1/C4 band-stop and L2/C5 band-stop filtering removes the main frequency band 564K and 287K of the C1 signal, and then removes the high-frequency interference through the filter capacitor C3. Finally, the comparator U2 and the preset level signal Vref3 perform level inversion. The high level indicates that the energy of C6 is insufficient, and the low level indicates that the energy of the C6 signal meets the requirements.

To sum up, the present invention provides an analog demodulation circuit for obtaining a message through the C interface of a ground electronic unit, and innovatively designs a C1 signal analog demodulation unit, so as to realize the analog demodulation and logic decoding of the C1 message signal with low cost, low cost, and low cost. The utility model has the characteristics of strong practicability, and at the same time, the invention also innovatively designs the C6 signal energy detection unit to realize the energy detection of the C6 signal, which has unique advantages compared with other equipment manufacturers.

The present invention provides an analog demodulation circuit for obtaining messages from the C interface of the ground electronic unit, which is simpler and more efficient, and can be used to conveniently manufacture test instruments, which can be applied to on-site engineering debugging and verification of C interface signals. And logic decoding, which can realize real-time demodulation and judge the accuracy or bit error rate of the message sent by the LEU, and add a C6 signal energy detection circuit to enrich the C interface test completion.

It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any relationship between these entities or operations. any such actual relationship or sequence exists. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device comprising a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

While the content of the present invention has been described in detail by way of the above preferred embodiments, it should be appreciated that the above description should not be construed as limiting the present invention. Various modifications and alternatives to the present invention will be apparent to those skilled in the art upon reading the foregoing. Accordingly, the scope of protection of the present invention should be defined by the appended claims.

Claims (8)

1. a ground electronic unit C interface obtains a message analog demodulation circuit, is characterized in that, comprises: The interface circuit unit is connected with the C interface of the ground electronic unit, and is used for receiving the C interface signal; The mutual inductance coil T1 is connected to the interface circuit unit and is used for collecting voltage induction signals; The C1 signal analog demodulation unit is connected to the mutual inductance coil T1, and is used to filter out the C1 signal from the voltage induction signal and generate a DBPL encoded signal; A C6 signal energy detection unit, connected to the mutual inductance coil T1, is used to filter out the C6 signal from the voltage sensing signal and detect the energy of the C6 signal; A signal processing unit, respectively connected to the C1 signal analog demodulation unit and the C6 signal energy detection unit, for decoding the DBPL encoded signal generated by the C1 signal analog demodulation unit, and judging whether the energy of the C6 signal is fulfil requirements; The interface circuit unit includes: a TVS protection tube, an LC band-pass filter module and a matching resistor, wherein the LC band-pass filter module and the matching resistor are connected in series with the TVS protection tube, and the matching resistor is connected in parallel with the TVS protection tube. It is connected in parallel with the input end of the mutual inductance coil T1. 2 . The analog demodulation circuit for obtaining a message through the C interface of the ground electronic unit according to claim 1 , wherein an FPGA is used as the signal processing unit. 3 . 3. the ground electronic unit C interface as claimed in claim 1 obtains the message analog demodulation circuit, it is characterised in that the C1 signal analog demodulation unit comprises a high-pass filter circuit module, a direct-pass traffic capacitor and a comparison circuit connected in sequence module; The high-pass filter circuit module is connected to the output end of the mutual inductance coil T1, the voltage sensing signal is filtered out by the high-pass filter circuit module to filter out the C1 signal, and after passing through the DC blocking capacitor, it is connected to the comparison circuit module Generate DBPL encoded signal and output. 4. the ground electronic unit C interface as claimed in claim 3 obtains the message analog demodulation circuit, it is characterized in that, described high-pass filter circuit module comprises two branches in parallel, wherein one branch comprises the resistance R1 and Capacitor C1, the other branch includes resistor R2, and the impedance of the two branches is different. 5. The analog demodulation circuit for obtaining a message from the ground electronic unit C interface according to claim 3, wherein the comparison circuit module comprises a first DC bias circuit, a second DC bias circuit and a comparator, The first DC bias circuit generates a first bias voltage, the second DC bias circuit generates a second bias voltage, and is connected to the first bias through the C1 signal of the DC blocking capacitor. The set voltage and the second bias voltage are generated by the comparator to generate a DBPL coded signal and output through a pull-up resistor. 6. The ground electronic unit C interface as claimed in claim 1 obtains a message analog demodulation circuit, wherein the C6 signal energy detection unit comprises a rectifier circuit module, a filter circuit module and a comparator connected in sequence; The rectifier circuit module is connected to the output end of the mutual inductance coil T1, the voltage induction signal generates a unipolar level signal through the rectifier circuit module, and the unipolar level signal is connected to the filter circuit module The C6 signal is filtered out, and then compared with the preset level signal by the comparator to detect the energy of the C6 signal. 7 . The analog demodulation circuit for acquiring a message through the C interface of the ground electronic unit according to claim 6 , wherein the rectifier circuit module comprises a full-bridge diode. 8 . 8 . The analog demodulation circuit for acquiring a message from the ground electronic unit C interface according to claim 6 , wherein the filter circuit module comprises two branches connected in parallel, and one branch comprises two LC circuits connected in series. 9 . , and the other branch includes a filter capacitor C3.

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